Aqueous mixture of surface active agents



3,095,353 AQUEOUS MIXTURE OF SURFACE ACTIVE AGENTS John M. Surgant,Richmond Heights, Mo., assignor to Monsanto Chemical Company, St. Louis,Mo., a corporation of Delaware No Drawing. Filed Mar. 30, 1960, Ser. No.18,507

6 Claims. (Cl. 167-43) This invention relates to an aqueous mixture ofsurface-active agents which exert a synergistic action, ne1thersurface-active agent alone being effective.

'From a practical 'standpoint'the manufacturer of' a' water-insolublepesticidal agent must supply the agriculturist with a low-costconcentrate thereof in such form that by merely mixing with Water at thepoint of use he will have an easily prepared pesticidal spray. It hasbeen customary in the preparation of concentrates that suchwater-insoluble pesticidal agents be dissolved in an organic solventtherefor and to admix with the organic solution a water-solublesurface-active agent. As those skilled in the art are well aware, thespecifications for an emulsifying and/or wetting agent in packaged goodswhich must withstand the effects of storage are exacting. The passage oftime and changes of temperature encountered in normal storage oftenmaterially effect the emulsifying and/or wetting properties of thesurfaceactive agent. Additionally the surface-active agent may reactwith the pesticidal agent or be otherwise affected by it over a periodof time and thus cause the active ingredient to lose or materiallylessen its pesticidal properties. Also in many instances while aparticular waterinsoluble pesticidal agent may be highly useful incombatting certain pests its usage has been limited or negatived byvirtue of the particular organic solvent employed to solubilize it, e.g.o-ily films and/r objectionable odor or solvent residues afterapplication and for other reasons those skilled in the art arethoroughly familiar.

In accordance with this invention it has been found that the combinationof about 1 to 2 parts by weight of (a) alkali metal alkyl sulfatewater-soluble anionic surfactant, about 1 to 3 parts by weight of (b)the condensation product of 1 mole of a mono-higher fatty acid ester ofhexitol anhydrides, i.e. sorbitan (C H O mannitan, sorbide (C H Omannide etc. with 10 to 30 moles of alkylene oxide, and 2 to 6 parts byweight of (c) water provides a homogeneous water-soluble surfaceactivemixture which fulfills the rigorous requirement of emulsifying and/ orwetting agents which must Withstand storage as concentrates. Optimumresults are obtained when the weight ratio of (a) to (b) to (c) is1:213.

By alkali metal alkyl sulfate as employed herein and in the appendedclaims is meant water-soluble anionic surfactants of the structure RO.SO.OM wherein R is a long chain alkyl radical (either straight orbranched) containing from 8 to 18 carbon atoms as exemplified by octyl,nonyl, decyl, undecyl, dodecyl, tridecyl, pentadecyl, cetyl, octadecyl,and the various isomeric forms thereof, and wherein M is an alkali metalsuch as sodium, potassium or lithium. It is preferred that R be astraight chain alkyl radical.

By mono-higher fatty acid ester of hexitol anhydrides as employed hereinand in the appended claims is meant mono-esters of hexitol anhydridesand a higher fatty acid such as lauric acid, palrnitic acid, oleic acid,ricinolcic acid, stearic acid and the like fatty acids containing from12 to 20 carbon atoms. As exemplary of such esters are sorbitanmono-laurate, mannitan mono-laurate, sorbitan mono-palmitate, sorbitanmono-oleate, mannitan mono-oleate, sorbide mono-oleate.

By alkylene oxide as employed herein and in the appended claims is meantethylene oxide and propylene 3,095,353 Patented June 25, 1963 oxide andmixtures thereof. These materials can be represented by the empiricalformula C H O wherein n is a whole number from 2 to 3. The preferredalkylene oxide is ethylene oxide.

Typical mixtures of the surface-active agents of this invention comprise(in parts by weight) I i B 0 Sodium lauryl sulfate 1 l 2 1 mole ofsorbitan monooleate condensed with 20 moles of ethylene oxide 1 2VVatcrt 0-... 3 2 6 These aqueous mixtures of surface-active agents,i.e.

compositions A, B and C, are clear liquids soluble in water.

The mixture of surface-active agents of this invention is characterizedby excellent stability. To demonstrate such the following respectivecompositions (in parts by 1 Commercial water-soluble anionic wettingagent.

2 Commercial water-soluble anionic emulsifying agent. were prepared byinitially mixing the sorbitan monooleate-ethylene oxide condensationproduct with a solution of the recited anionic surfactant in the waterand passing the mix and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinolinethrough a colloid mill. The resulting concentrates were then permittedto stand in closed containers under normal storage conditions.Compositions B, C, D, E, F and G after 2 days showed oiling out of 6-ethoxy-2,2,4-trimethyl-1,Z-dihydroquinoline while composition A afterstanding 5 months showed no signs of oiling out of6-ethoxy-2,2,4-trimethyl-l,Z-dihydroquinoline. Further Composition Aafter standing for 5 months was still self-emulsifiable with Water.

2,2,4-trimethyl-1,2-dihydroquinolines, such as 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline which is a waterinsoluble yellowoily liquid, have been found to be useful in the control of common applescald and Anjou pear scald and for preserving the nutritive value offeeds and forage plants, particularly alfalfa. However their usage hasbeen curtailed by virtue of the organic solvents (usually high molecularWeight alcohols such as decyl alcohol and dodecyl alcohol) employed tomake concentrated solutions thereof because of injury to the treatedsurface as well as objectionable odors and/or oily films characterizingthe residues after application in the field. Further to date,no-water-soluble surface-active agent in admixture with suchconcentrated organic solutions has provided a concentrate capable ofwithstanding the effects of storage. The aqueous surface-active mixtureof this invention is soluble in 2,2,4-trimethyl-l,2-dihydroquinolinessuch as 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline and providessolventless concentrates which are self-emulsifiable in water.Concentrates containing 0.5 to 8.0 but preferably 1.5 to 2.5 by weightof 2,2,4-trimethyl-1,Z-dihydroquinoline per 1 part by weight of theaqueous surface-active agent mixture of this invention exhibit goodstability in storage and excellent self-emulsifying properties whenadmixed with water at the point of use.

The aqueous surface active mixture of this invention aforementioned isuseful in preparing emulsifiable concentrates of other2,2,4-trimethyl-1,2-di'hydroquinolines as for example those disclosed inU.S. 2,562,970 (issued August 7, 1951) of the structure wherein R ishydrogen, a hydrocarbon radical or a hydrocarbonoxy radical (e.g.methyl, ethyl, isopropyl, nbutyl, isobutyl, hexyl, phenyl, benzyl,methoxy, ethoxy, propoxy, isoamyloxy, ph'enoxy, benzyloxy, etc.) containing not more than 7 carbon atoms.

While this invention has been described with respect to certainembodiments it is to be understood that it is not so limited and thatvariations and modifications thereof obvious to those skilled in the artcan be made without departing from the spirit or scope of thisinvention.

What is claimed is: g

1. A homogeneous mixture of surface-active agents for emulsifying anddispersing water-insoluble substances in water which mixture iswater-soluble and contains from about 1 to 2 parts by weight of (a) analkali metal alkyl sulfate water-soluble surfactant of the structureRO.SO .OM wherein R is a long chain alkyl radical containing 8 to 18carbon atoms and wherein M is an alkali metal, about 1 to 3 parts byweight of (b) the watersoluble condensation product of a mono-higherfatty acid ester of hexitol anhydride with 10 to 30 moles of alkyleneoxide of the empirical formula C H O wherein n is a whole number from 2to 3 per mole of ester, and 2 to 6 parts by weight of (c) water.

2. The composition of claim 1 wherein the weight ratio of (a) to (b) to(c) is 1:2:3.

3. An emulsifiable concentrate containing 0.5 to 8.0 parts by weight ofa 2,2,4-trim'ethyl-1,2-dihydroquinoline and 1 part by weight of thecomposition of claim 1.

4. An emulsifiable concentrate containing 1.5 to 2.5 parts by weight of6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline and 1 part by weight ofthe composition of claim 2.

5. An emulsifiable concentrate containing 1.5 to 2.5 parts by weight of6-ethoxy-2,2,4-trimethyl-1,Z-dihydroquinoline and 1 part by weight of amixture of (a) sodium lauryl sulfate, (b) water-soluble condensationproduct of 1 mole of sorbitan mono-oleate with 10 to 30 moles ofethylene oxide, and (c) water, the weight ratio of (a) to (b) to (0)being 1:2:3.

6. A homogeneous mixture of surface-active agents for emulsifying anddispersing water-insoluble substances in water which mixture iswater-soluble and contains from about 1 to 2 parts by weight of sodiumlauryl sulfate, about 1 to 3 parts by weight of the water-solublecondensation product of one mole of sorbitan monooleate with 10 to 30moles of ethylene oxide, and 2 to 6 parts by weight of water.

References Cited in the file of this patent UNITED STATES PATENTS Re.24,184 Sanders et a1. July 24, 1961 2,372,807 Brown Apr. 3, 19452,509,233 Kaberg et a1. May 30, 1950 2,562,970 Thompson Aug. 7, 19512,845,380 Mayhew et al. July 29, 1958 2,870,058 Loder Jan. 20, 19-592,872,368 Sanders et a1. Feb, 3, 1959 2,898,267 Lindner Aug. 4, 19592,946,721 Hyatt et al. July 26, 1960 OTHER REFERENCES Schwartz et al.:Surface Active Agents and Detergents, Interscience Publishers, Inc., NY.1958, vol. II, pp. 205, 209, 231, 232-235, 238-241, 318-322, 380-381,383, 607, 611, 652- 6. Esp. pertinent pages of Schwartz et al.,disclosing enhanced effects arising from surfactant adjuvation ofresidual plant sprays, are on pages 652-656.

1. A HMOMGENEOUS MIXTURE OF SURFACE-ACTIVE AGENTS FOR EMULSIFYING ANDDISPERSING WATER-INSOLUBLE SUBSTANCES IN WATER WHICH MIXTURE ISWATER-SOLUBLE AND CONTAINS FROM ABOUT 1 TO 2 PARTS BY WEIGHT OF (A) ANALKALI METAL ALKYL SULFATE WATER-SOLUBLE SURFACTANT OF THE STRUCTURERO.SO2OM WHEREIN R IS A LONG CHAIN ALKYL RADICAL CONTAINING 8 TO 18CARBON ATOMS AND WHEREIN M IS AN ALKALI METAL, ABOUT 1 TO 3 PARTS BYWEIGHT OF (B) THE WATERSOLUBLE CONDENSATION PRODUCT OF A MONO-HIGHERFATTY ACID ESTER OF HEXITOL ANHYDRIDE WITH 10 TO 30 MOLES OF ALKYLENEOXIDE OF THE EMPIRICAL FORMUAL CNH2NO WHEREIN N IS A WHOLE NUMBER FROM 2TO 3 PER MOLE OF ESTER, AND 2 TO 6 PARTS BY WEIGHT OF (C) WATER.